Wound capacitor and method of manufacture thereof



Oct. 2, 1956 P. A. w. M. SLEEGERS 2,765,432

WOUND CAPACITOR AND METHOD OF MANUFACTURE THEREOF Filed 001;. l, 1952 INVEN TOR AULUS ANTONIUS WILHELMUS MARIA SLEEGERS AGENT United StatesPatent WOUND CAPACITOR AND METHOD OF MANUFACTURE THEREOF Paulus AntoniusWilhelmus Maria Sleegers, Eindhoven, Netherlands, assignor to HartfordNational Bank and Trust Company, Hartford, Conn., as trustee ApplicationOctober 1, 1952, Serial No. 312,524

Claims priority, application Netherlands October 13, 1951 6 Claims. (Cl.317-260) For the current supply to the coating of a wound capacitor usemay be made of a strip-shaped connecting electrode which is inserted inthe winding and projects therefrom at the top. It is known that, due tosharp edges of the strip the dielectric may break down at the area ofthe strip and it has therefore been suggested to reinforce thedielectric at that area.

The invention relates to a method of manufacturing a wound capacitorcomprising one or more connecting electrodes inserted in the winding andprojecting at the top and a dielectric which is reinforced at theseareas.

According to the invention a folded strip of insulating material,together with a connecting electrode introduced through an aperture inthe folded edge is put, by way of rider, on the edge of a portion of thecoating which has not yet been wound up, during the winding of thecapacitor, the connecting electrode thus coming into contact with thecoating.

Thus not only the connecting electrode may be readily inserted but alsothe dielectric is reinforced at the area of the connecting electrode.

The connecting electrode is preferably stuck to one of the foldedportions of the insulating strip. The folded strip portions may,moreover, have different lengths. If such a rider is moved transverselyto the plane of the coating along the edge thereof, so that the longerof the folded portions is retained by the edge, the folded portions ofthe strip diverge from one another, which facilitates the introductionof the rider.

In order that the invention may be readily carried into effect, it willnow be described in detail wtih reference to the accompanying drawing,in which:

Fig. 1 shows diagrammatically a wound capacitor during its manufactureaccording to the invention, and

Fig. 2 is part of an axial sectional view of a winding manufactured bythe method according to the invention.

Referring to Fig. 1, reference numeral 1 designates a winding mandrel 1,on which a capacitor 2 is wound. The capacitor is obtained by winding uptwo thin strips of metal 3 and 4, for example, tin or aluminium foil,which are separated electrically from one another by two strips ofdielectric material 5 and 6 and 7 and 8 respectively, wound togetherwith the foils. The dielectric strips, which may, for example, be ofpaper, are slightly broader than the metal strips.

During the winding operation, a doubled dielectric strip 9 is put, byway of rider, on the edge of the coating 3. The folded edge of thisstrip has an aperture 10. A connecting strip 11 is introduced throughthis aperture, so that part of this strip is located between the partsof the strip 9, folded on one another. When arranging the rider on theedge of the coating 3, the two parts of the strip 9 being one on eachside thereof, the part of the strip 11 inserted in the strip 9 comesinto contact with the coating 3 and is pressed against it when thecapacitor is wound up. Where the connecting strip is provided, thedielectric is reinforced on each side of the coating by the strip2,765,432 Patented Oct. 2, 1956 9. Thus sharp edges of the connectingstrip 11 are prevented from damaging the dielectric, so thatconcentrations of the electric field such that electrical break-downoccurs are avoided.

If, as in the aforesaid case, the coatings are constituted by metalfoils, it makes no difference on which side thereof the connecting strip11 is located. If the coating is constituted by a thin metal layer on aninsulating carrier, for example, a thin layer of zinc or aluminiumapplied by vaporisation on a strip of paper or polystyrene, provisionmust be made that the connecting strip is on that side of the carrierwhere the metal layer is provided. Before the rider is put on thecoating, the connecting strip 11 may be stuck to one of the folded partsof the strip 9, so that in placing the folded strip in such a way on thecarrier that the portion with the supply strip glued thereon is on theside of the coating, the desired electrical contact between the supplystrip and the coating is ensured.

The proper arrangement of the folded insulating strip is facilitated andeasily checked, if the doubled strip portions, as is shown in Figure 2,are of different length. For placing the insulating strip on anelectrode foil or the carrier of a metallic coating in the manufactureof a condenser according to the invention the two portions of thedoubled strip may be made to diverge on approach of the electrode byfirst letting only the part of the longer portion extending beyond theend of the shorter portion rest on the edge of the electrode foil or, asthe case may be, the carrier of the coating, and thereupon slightly movethe strip transversely to the plane of the electrode in the properdirection. The longer portion is held back, so that between the foldedportions a space is created in which the edge of the electrode is easilyinserted by proper movement of the doubled strip.

Fig. 2 shows part of the winding manufactured by the method describedwith reference to Fig. l in a sectional view taken on the connectingstrip 11. The coating 3 and 4 are shown and the thicknesses of thevarious strips which are in direct contact with one another are shown onan exaggerated scale. The reinforcement of the dielectric, separatingthe two coatings 3 and 4 at the area of the connecting strip 11 isclearly shown.

What I claim is:

1. A method of manufacturing a wound capacitor comprising the steps ofwinding a plurality of metal strips on a mandrel, said strips beingseparated electrically from each other by strips of dielectric material,folding a separate strip of insulating material around one of said metalstrips, said folded strip of insulating material being provided with anaperture through its folded edge, and placing a connecting electrodethrough said aperture and into intimate contact with an unwound portionof said one of said metal strips.

2. A method as set forth in claim 1 wherein said connecting electrode isadhered to one of the folded portions of said folded strip.

3. A method as set forth in claim 1 wherein one of said folded portionsof said folded strip is longer than the other, the longer portion beingcaused to bear on the edge of said one of said metal strips before saidconnecting electrode is inserted in said aperture by moving saidelectrode in a direction transverse to the plane of said metal strips,and said two folded portions diverging from one another.

4. A wound capacitor comprising a plurality of thin metal strips, aplurality of dielectric strips disposed between said metal strips, allof said strips being wound into a cylindrical form, a separate strip ofinsulating material folded over one of said metal strips, said foldedstrip having an aperture therein, and a connecting electrode in saidaperture having part thereof engaging said one of" said metal strips andpart thereof projecting 1aterally from said WOlJIld' capacitor.

5. A Wound capacitor comprising, a plurality of thin metal strips, aplurality of dielectric strips each having a greater width than saidmetal strips, said strips being disposed between said metal strips, allof said strips being, Wound into a cylindrical form, a separate strip ofinsulating material folded over one of said metal strips, said foldedstrip having an aperture therein, and a connecting electrode in saidaperture having one surface thereof secured to a portion of said foldedstrip and another surface engaging said one of said metal strips.

6. A wound capacitor comprising a plurality of thin metal strips, aplurality of dielectric strips each having a greater Width than saidmetal strips, said strips being disposed between said metal strips, allof said strips being Woundinto a cylindrical form, a separate strip ofinsulating material folded over one of said metal strips, said folded.strip having an aperture therein and one leg longer than the other leg,and a connecting electrode in said aperture having part thereof engagingsaid one of said metal strips and part thereof projecting laterally fromsaid wound capacitor.

References Cited in the file of this patent UNITED STATES PATENTS2,495,734- Katzman et all Jan. 31, 1950' 2,547,644 Hogue et a1. Apr.3",, 1951 FOREIGN PATENTS 476,155 Great Britain Dec. 2, 1937

